NotionQL allows you to pass a sorts argument to your GraphQL queries. Sorts is an array of Sort Objects that specify the order of the results.
Like filters, the value of the property key is the unsanitized format of the property name in your Notion Database. For example, if you property name in your Notion Database is Last Updated, then you would pass property: "Last Updated" to your sort.
For more details on the structure of a Sort Object, see the Notion API documentation.